Studies proposed under this grant employ synthetic oxygen-binding iron chelates prepared by Dr. J. Baldwin and coworkers of M.I.T. The major purpose is to devise artificial blood substitutes utilizing these chelates as the oxygen transport vehicle. The utlimate goal is to obtain complete replacement of blood in animals using such substitutes. Suitability for organ perfusion in vitro will also be tested. The studies involve setting up analytical procedures for the chelates and their metabolic products, determining the effectiveness of the chelates as oxygen carriers under biologic conditions, ascertaining the biologic fate of the chelates. The results of these projects will be used in determining additional compounds to by synthesized. Ultimately compounds with long dwell times in circulation will be sought. Free-hemoglobin will be used as a model compound for making comparisons with the artificial agents.